California C-10 Electrical Contractor
License Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2025 Q&A | Instant
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1. What is the minimum depth for a direct-buried cable in residential
landscaping areas?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
NEC Table 300.5 requires a minimum of 18 inches for residential
branch circuits using direct burial cable.
2. Which of the following wire colors is typically used for a neutral
conductor in a residential setting?
A. Red
B. Green
, C. White
D. Black
NEC requires neutral conductors to be white or gray in color.
3. What is the allowable ampacity of a #8 AWG copper conductor with
THHN insulation at 75°C?
A. 40 amps
B. 50 amps
C. 55 amps
D. 60 amps
According to NEC Table 310.16, #8 THHN copper conductor has an
ampacity of 50 amps at 75°C.
4. What must be done before energizing a new service?
A. Connect grounding only
B. Turn off all breakers
C. Obtain an inspection and approval
D. Notify the fire department
A licensed inspector must approve the installation before utility
service is energized.
5. What is the minimum working space required in front of a 480V
electrical panel?
A. 24 inches
B. 36 inches
C. 48 inches
, D. 60 inches
Per NEC 110.26, 36 inches of clearance is required for equipment up
to 600 volts.
6. Which document verifies that an electrical contractor is licensed to
work in California?
A. CSLB Compliance Form
B. OSHA Card
C. C-10 Contractor License
D. Electrical Permit
Only the C-10 license, issued by the CSLB, permits electrical
contracting in California.
7. How often should GFCIs be tested according to manufacturers?
A. Monthly
B. Yearly
C. Weekly
D. Bi-annually
GFCI manufacturers and NEC recommend monthly testing for safety.
8. A ground rod must be driven to a minimum depth of:
A. 4 feet
B. 6 feet
C. 8 feet
, D. 12 feet
NEC 250.53(G) requires ground rods to be at least 8 feet into the
earth.
9. What is the main purpose of bonding?
A. Provide lighting
B. Reduce wire usage
C. Ensure conductive paths for fault current
D. Limit electromagnetic fields
Bonding creates a low-impedance path to carry fault current safely.
10. What is required for an overhead service drop clearance above
residential driveways?
A. 8 feet
B. 10 feet
C. 12 feet
D. 15 feet
NEC 230.24(B) requires 12 feet of clearance over residential
driveways.
11. Which type of conduit is approved for direct burial without
additional protection?
A. EMT
B. PVC Schedule 80
C. IMC
License Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2025 Q&A | Instant
Download Pdf
1. What is the minimum depth for a direct-buried cable in residential
landscaping areas?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
NEC Table 300.5 requires a minimum of 18 inches for residential
branch circuits using direct burial cable.
2. Which of the following wire colors is typically used for a neutral
conductor in a residential setting?
A. Red
B. Green
, C. White
D. Black
NEC requires neutral conductors to be white or gray in color.
3. What is the allowable ampacity of a #8 AWG copper conductor with
THHN insulation at 75°C?
A. 40 amps
B. 50 amps
C. 55 amps
D. 60 amps
According to NEC Table 310.16, #8 THHN copper conductor has an
ampacity of 50 amps at 75°C.
4. What must be done before energizing a new service?
A. Connect grounding only
B. Turn off all breakers
C. Obtain an inspection and approval
D. Notify the fire department
A licensed inspector must approve the installation before utility
service is energized.
5. What is the minimum working space required in front of a 480V
electrical panel?
A. 24 inches
B. 36 inches
C. 48 inches
, D. 60 inches
Per NEC 110.26, 36 inches of clearance is required for equipment up
to 600 volts.
6. Which document verifies that an electrical contractor is licensed to
work in California?
A. CSLB Compliance Form
B. OSHA Card
C. C-10 Contractor License
D. Electrical Permit
Only the C-10 license, issued by the CSLB, permits electrical
contracting in California.
7. How often should GFCIs be tested according to manufacturers?
A. Monthly
B. Yearly
C. Weekly
D. Bi-annually
GFCI manufacturers and NEC recommend monthly testing for safety.
8. A ground rod must be driven to a minimum depth of:
A. 4 feet
B. 6 feet
C. 8 feet
, D. 12 feet
NEC 250.53(G) requires ground rods to be at least 8 feet into the
earth.
9. What is the main purpose of bonding?
A. Provide lighting
B. Reduce wire usage
C. Ensure conductive paths for fault current
D. Limit electromagnetic fields
Bonding creates a low-impedance path to carry fault current safely.
10. What is required for an overhead service drop clearance above
residential driveways?
A. 8 feet
B. 10 feet
C. 12 feet
D. 15 feet
NEC 230.24(B) requires 12 feet of clearance over residential
driveways.
11. Which type of conduit is approved for direct burial without
additional protection?
A. EMT
B. PVC Schedule 80
C. IMC
